This invention relates to personal cleansing bar soaps prepared from soap using a "freezer" bar process of the general type disclosed in U.S. Pat. No. 3,835,058, White, issued Sep. 10, 1974, incorporated herein by reference. These bars are called "freezer bars," and White teaches a freezer bar soap process. The White freezer bars and the present day standard freezer bar, disclosed herein, have bad bathtub ring (BTR).
Soap bars when lathered and solubilized in hard water (hard water being defined as water containing calcium as CaCO.sub.3 or CaCl.sub.2) form calcium soap on the walls of the bathtub or shower enclosure. This film, referred to as bathtub ring (BTR), is difficult to clean and therefore preventing its formation is desirable. Personal cleansing products designed to not form insoluble calcium soap (BTR) or to disperse it and not allow it to deposit on the shower or bath enclosure are considered consumer preferred.
A freezer bar process is distinguished from a transparent framed bar process. Japanese Pat. J5 7030-798, Jul. 30, 1980, discloses transparent solid "framed" or "molded" soap in which fatty acids constituting the soap component are myristic, palmitic, and stearic acids. A transparent soap is described in which at least 90 wt. % of the fatty acids which constitute the soap component are myristic acid, palmitic acid, and stearic acid. The product is reported as a transparent, solid soap having good frothing and solidifying properties, good storage stability, and a low irritant effect on human skin. The process and transparent bar soap composition exemplified in Jap. J5 7030-798 do not appear to contain synthetic surfactant and are believed to be distinguished from nontransparent freezer bars.
U.S. Pat. No. 2,988,511, Mills and Korpi, issued Jun. 13, 1961, for a nonsmearing "milled" detergent bar with at least 75% by weight of which consists essentially of (1) from about 15% to about 55% of normally solid detergent salts of anionic organic sulfuric reaction products which do not hydrolyze unduly under conditions of alternate wetting and drying, said salts being selected from the group consisting of the sodium and potassium salts, and said anionic organic sulfuric reaction products containing at least 50% alkyl glyceryl ether sulfonates from about 10% to about 30% of which alkyl glyceryl ether sulfonates are alkyl diglyceryl ether sulfonates, the alkyl radicals containing from about 10 to about 20 carbon atoms; (2) from about 5% to about 50% of a water-soluble soap of fatty acids having from about 10 to about 18 carbon atoms; and (3) from about 20% to about 70% of a binder material selected from the group consisting of freshly precipitated calcium soaps of fatty acids having from about 10 to about 18 carbon atoms, freshly precipitated magnesium soap of fatty acids having from about 10 to about 18 carbon atoms, starch, normally solid waxy materials which will become plastic under conditions encountered in the milling of soap and mixtures thereof. This Mills/Korpi patent is incorporated herein by reference. Freezer soap bars are distinguished from milled soap bars.